It seems to me that you are attempting this inside Simulation Professional with the drop test module. The geometry is a weldment structure, which should ideally be meshed using beams, or at least a mixed mesh approach with the majority being beams. However, the drop test module you are using will not permit any other type of meshing scheme other than Solids (Tetrahedrons).

This problem should be attempted using the Sim Premium package (next level up). This allows you to use mixed meshing in either a Linear Dynamic or a Non-Linear dynamic environment to either step in frequency or time respectively. The Linear Dynamic approach would be to use Modal Time History and specify the impact load concentration and magnitude as a function of time. This approach will save a lot of time because of going into the frequency domain and de-coupling the equations. However, the material stays linear and elastic, and no contacts are considered (all bodies are perfectly bonded).

The Non-Linear Dynamic environment will be more time consuming (explicit time integration, or implicit time integration), since it steps in the time domain. However, the materials can go non-linear (plasticity within reason can be considered) and contacts can be described.

I would recommend either of the above two approaches rather than attempting this problem with the drop test module. The drop test module is ideally suited for bulkier bodies which have comparable dimensions in all three directions.